Field of the Technology
The invention relates to the field of photonics technology and principles of optical coherence tomography for use in the characterization of multiple properties of gemstones, including, but not limited to diamonds.
Description of the Prior Art
Currently, gem weight (carat) assessment is performed on stones that remain within the setting as an estimate, or the stones must be removed from the setting for accurate appraisal. These appraisals are classified as an estimate or measure depending on whether the gem remained in the setting or was removed for analysis. Removing the stones from the settings is expensive, time-consuming, and can result in damage to the settings.
There is significant variation in weight estimate for stones left in settings. This can lead to many thousands of dollars of differences in value with significant impact on purchase price, insurance costs, and claims.
With regard to determination of flaws, the process generally involves the gemologist examining under a light microscope at 10× magnification, and mapping out areas where they see significant flaws. There are some sophisticated methods for gem identification based on flaws and photography. There are, however, no reasonably accessible three-dimensional flaw mapping or recording capabilities or methods.
Additionally, stones can have laser-based inclusion ablations that can affect the value. Stones can have cracks and flaws. These cracks can be native, or can be filled by addition of molten glass or other processes that reduce their value. Mapping of such flaws would also be of great value in the industry. Stones have a “fingerprint” of flaws and inclusions that could be used to identify them. It would be useful to provide detailed, easily accessible, three dimensional maps of gem characteristics for identification purposes.
What is needed is a precise, accurate, inexpensive and objective method and apparatus for diamond and gemstone characterization, including determination of size (carat weight), clarity (flaw/inclusion mapping and assessment), cut grading, color determination, and mapping of cracks in intact stones within or outside settings and in uncut stones. In addition, characterization of inclusions and other methods for differentiating synthetic from natural gemstones are needed